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Accounts Receivable (Details) - USD ($)
Sep. 30, 2021
Dec. 31, 2020
Summary of accounts receivable    
Total gross receivables $ 4,523,732 $ 3,431,522
Less: allowance for doubtful accounts (957,116) (795,914)
Total net receivables 3,566,616 2,635,608
Construction services [Member]    
Summary of accounts receivable    
Total gross receivables 3,066,890 1,391,555
Engineering services [Member]    
Summary of accounts receivable    
Total gross receivables 34,919 86,264
Medical [Member]    
Summary of accounts receivable    
Total gross receivables 408,619 1,157,819
Retainage receivable [Member]    
Summary of accounts receivable    
Total gross receivables 615,136 615,136
Other receivable [Member]    
Summary of accounts receivable    
Total gross receivables $ 398,168 $ 180,748